The present invention relates to a power controller, for example a controller for a motor in a battery-operated vehicle. Such controllers typically have to switch large currents at low voltages (eg currents of the order of 500 A at 24 V or 48 V), and typically use control circuit comprising a bank of switching elements, and a capacitor. A first switching element may be a MOSFET transistor and a second switching element a diode (i.e. a passive switching element); alternatively, both switching elements may be MOSFET transistors. It will of course be realized that such controllers may also have application beyond battery-operated vehicles, in other situations in which large currents have to be controlled.
An object of at least the preferred embodiments of the present invention is to minimize the size and cost of such controllers.
According to one aspect of the invention there is provided a power controller, comprising a plurality of switching circuits each consisting of a first switching element, a second switching element, and a capacitor, and a printed circuit board having the switching circuits arranged around an inner area of the board in a partial or complete loop, the inner area of the board and the area outside the loop (the outer area) being substantially solid tracking areas forming the sole connections to the switching circuits.
The inner area on both sides of the board and the outer area on at least one side may form the connections to the circuits.
The switching circuits may be arranged in four sets, each set parallel to a respective edge of the board.
Preferably the connectors to circuits are located substantially along a diagonal of the board, with the connectors to the two sides of the diodes located at opposite comers of the inner areas of the board. The parts of at least one of the tracking areas adjacent to the circuits are preferably divided by isolating lines into separate fingers for the respective circuits.
According to another aspect of the invention there is provided a power controller, comprising a switching circuit consisting of a first switching element, a second switching element, and a capacitor, mounted on a printed circuit board with the first and second switching elements mounted on one face of the board and the capacitor on the other.
Preferably a heat sink is located between the switching elements to receive heat therefrom. There may be means mechanically fixing the switching elements to each other via the heat sink. Thus the switching elements may be clamped to the heat sink, preferably by a nut and bolt passing through lugs on the switching elements and a matching hole in the heat sink, which may be of bar-like configuration. There may be a plurality of switching circuits arranged in a row with a common heat sink. A heat dissipating element eg. a plate substantially parallel to the printed circuit board may be attached to the heat sink.